It's very likely that at that weight, you don't really have any to lose.
If you have visible abdominal muscles, you're not only at a healthy weight, you're at a reasonably low body fat level.
It's not a good idea to set a weight goal without knowing your lean weight/body fat percentage.
When I was your age, I was 5-7, 130 lbs with muscular legs(I'm a guy) otherwise skinny as a rail and well under 10% body fat.
"To give anything less than your best is to sacrifice the Gift."